Swimming efficiency of bacterium Escherichia coli
Swimming efficiency of bacterium Escherichia coli
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DOI：
10.1073/pnas.0602043103
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发表时间：
2006-09-12
影响因子：
11.1
通讯作者：
Wu, X. L.
中科院分区：
文献类型：
--
作者：
Chattopadhyay, Suddhashil;Moldovan, Radu;Wu, X. L.
我们在一个光学陷阱中使用游动细菌的测量来确定细菌推进的基本特性。特别是，我们直接测量了将细菌保持在光学陷阱中所需的力，并确定了推进矩阵，该矩阵将鞭毛的平移速度和角速度与推动细菌的扭矩和力联系起来。从推进矩阵中，可以通过测量电机的角速度来获得扭矩、游泳速度和功率等动态特性。我们发现不同个体之间存在显著的异质性，尽管所有细菌都是从一个菌落开始的。推进效率，定义为推进功率输出与电机提供的旋转功率输入的比率，发现接近2%，这与理论上预测的刚性螺旋线圈的效率一致。
We use measurements of swimming bacteria in an optical trap to determine fundamental properties of bacterial propulsion. In particular, we directly measure the force required to hold the bacterium in the optical trap and determine the propulsion matrix, which relates the translational and angular velocity of the flagellum to the torques and forces propelling the bacterium. From the propulsion matrix, dynamical properties such as torques, swimming speed, and power can be obtained by measuring the angular velocity of the motor. We find significant heterogeneities among different individuals even though all bacteria started from a single colony. The propulsive efficiency, defined as the ratio of the propulsive power output to the rotary power input provided by the motors, is found to be approximate to 2%, which is consistent with the efficiency predicted theoretically for a rigid helical coil.